Apparatus and method of communication based on extended bandwidth and multi-resource unit in wireless local area network system

ABSTRACT

A method of communicating, by a first device, with at least one second device in a wireless local area network (WLAN) system includes allocating at least one resource unit (RU) within a bandwidth to a second device; generating at least one subfield defining the at least one RU; generating a trigger frame comprising a user information field comprising the at least one subfield, and transmitting a PPDU including the trigger frame to the at least one second device, wherein the generating comprises setting at least seven bits associated with the at least one RU and setting at least two bits as a value defining a subband that includes the at least one RU when the band width comprises at least four subbands.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. 120 of U.S. patentapplication Ser. No. 17/313,232, filed May 6, 2021, which is related toand claims priority under 35 U. S. C. § 119 to U.S. ProvisionalApplication No. 63/025,279 filed on May 15, 2020; U.S. ProvisionalApplication No. 63/073,628 filed on Sep. 2, 2020; U.S. ProvisionalApplication No. 63/089,275 filed on Oct. 8, 2020; U.S. ProvisionalApplication No. 63/094,686 filed on Oct. 21, 2020; U.S. ProvisionalApplication No. 63/106,128 filed on Oct. 27, 2020; U.S. ProvisionalApplication No. 63/109,024 filed on Nov. 3, 2020; U.S. ProvisionalApplication No. 63/118,788 filed on Nov. 27, 2020; and Korean PatentApplication No. 10-2021-0009755 filed on Jan. 22, 2021 in the KoreanIntellectual Property Office, the disclosures of which are incorporatedby reference herein in their entireties.

TECHNICAL FIELD

This disclosure relates generally to wireless communications and moreparticularly to an apparatus and method of communication based on anextended bandwidth and a multi-resource unit (multi-RU) in a wirelesslocal area network (WLAN) system.

DISCUSSION OF RELATED ART

WLAN is a technology for wirelessly connecting two or more devices toeach other, where the devices are located in a local environment such asa building or campus. A WLAN may in an infrastructure mode in which anaccess point (AP) serves multiple user devices such as smartphones andlaptops, where the AP may serve as a gateway to a remote network,typically the Internet. A WLAN alternatively operates as an ad hocnetwork between peer devices without an AP. In either case, WLAN employsorthogonal frequency division multiplexing (OFDM) technology in whicheach user device communicates with an AP or another user device using anassigned set of OFDM subcarriers within an overall frequency band of theWLAN.

Currently, most WLAN technology is based on the institute of electricaland electronics engineers (IEEE) 802.11 standard. The IEEE 802.11standard has been developed into 802.11b, 802.11a, 802.11g, 802.11n,802.11ac, and 802.11ax versions and may support a transmission speed upto 1 Gbyte/s through use of OFDM technology. In version 802.11ac, datamay be simultaneously transmitted to multiple users through a multi-usermulti-input multi-output (MU-MIMO) scheme. In 802.11ax (referred to asjust “high efficiency” (HE)), by providing available subcarriers tousers in a divided manner with orthogonal frequency division multipleaccess (OFDMA) technology, in conjunction with applying MU-MIMO,multiple access is implemented. The WLAN system to which 802.11ax isapplied may effectively support communication in a crowded area andoutdoors.

Another recent version, 802.11be (extremely high throughput (EHT)), isslated to support a 6 GHz unlicensed frequency band, a bandwidth up to320 MHz per channel, hybrid automatic repeat and request (HARQ), and upto 16×16 MIMO. Therefore, a next generation WLAN system is expected toeffectively support low latency and ultra-fast transmission withperformance metrics similar to new radio (NR) 5G technology.

SUMMARY

Embodiments of the inventive concept provide an apparatus and method ofefficiently allocating a multi-RU to a user within an extended uplinkbandwidth in a wireless local area network (WLAN) system.

According to an aspect, a method of communicating, by a first device,with at least one second device in a WLAN system may include allocatingat least one resource unit (RU) within a bandwidth to a second device.At least one subfield is generated defining the at least one RU. Thismay involve setting at least two bits as a value defining a subband thatincludes the at least one RU when the bandwidth comprises at least foursubbands. A trigger frame is generated including a user informationfield that includes the at least one subfield. A physical layer protocoldata unit PPDU) including the trigger frame is transmitted to the atleast one second device.

According to another aspect, a first device configured to communicatewith at least one second device in a WLAN system may include atransceiver configured to transmit a PPDU to the at least one seconddevice. The transceiver includes a signal processor configured toallocate at least one RU to the second device within a bandwidth,generate at least one subfield defining the at least one RU, generate atrigger frame including a user information field including the at leastone subfield, and generate the PPDU including the trigger frame. Thesignal processor is configured to set at least 7 bits associated withthe at least one RU and to set at least two bits as a value defining asubband including the at least one RU when the bandwidth comprises atleast four subbands.

According to another aspect, a method of communicating, by a seconddevice, with a first device in a WLAN system may include receiving aPPDU from the first device; extracting common information from the PPDUand extracting an uplink bandwidth field from the common information;extracting user information from the PPDU, and extracting at least onesubfield from the user information; and identifying at least one RUwithin a bandwidth, based on the uplink bandwidth field and the at leastone subfield. The identifying of the at least one RU includesidentifying, based on at least first and second bits of the at least onesubfield, a subband including the at least one RU when the bandwidthincludes at least four subbands.

According to another aspect, a method of communicating, by a firstdevice, with at least one second device in a WLAN system may includeallocating at least one RU within a bandwidth of 320 MHz to a seconddevice; and generating at least one subfield defining the at least oneRU, where the generating includes setting at least eight bits associatedwith the at least one RU and setting a first bit with a valuerepresenting one of the lower 160 MHz and the upper 160 MHz thatincludes the at least one RU when the bandwidth is 320 MHz and a totalbandwidth of the at least one RU is 160 MHz or less. A trigger frame isgenerated and a PPDU is transmitted as outlined above.

In another aspect, a method of communicating, by a first device, with atleast one second device in a WLAN system includes: allocating at leastone RU within a bandwidth including a plurality N of subbands to asecond device; generating at least one subfield defining the at leastone RU, where the generating comprises setting a plurality K of bitsassociated with the at least one RU, and setting M additional bits withvalues that collectively define one of the subbands including the atleast one RU, where M<N<K. A trigger frame is generated and a PPDU istransmitted as outlined above.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which like reference characters refer to likeelements throughout, wherein:

FIG. 1 is a view illustrating a wireless local area network (WLAN)system;

FIG. 2 is a block diagram illustrating a wireless communication devicetransmitting or receiving a physical layer convergence protocol (PLCP)protocol data unit (PPDU);

FIG. 3 is a view illustrating a structure of a high efficiency (HE)single user (SU) PPDU;

FIG. 4 is a view illustrating a structure of an HE extended range (ER)SU PPDU;

FIG. 5 is a view illustrating a structure of an HE trigger based (TB)PPDU;

FIG. 6 is a view illustrating a structure of an HE multiuser (MU) PPDU;

FIG. 7 is a view illustrating a structure of the HE-SIG-B field of FIG.6 ;

FIG. 8 is a view illustrating that the HE MU PPDU is arranged byfrequency band;

FIGS. 9A and 9B are diagrams illustrating examples of RUs available in a20 MHz OFDMA PPDU and indexes thereof;

FIGS. 10A and 10B are diagrams illustrating examples of RUs available ina 40 MHz OFDMA PPDU and indexes thereof;

FIGS. 11A and 11B are diagrams illustrating examples of RUs available inan OFDMA PPDU and indexes thereof;

FIGS. 12A and 12B are diagrams illustrating examples of indexes of RUsavailable in a 160 MHz OFDMA PPDU;

FIGS. 13A, 13B, 13C, 13D, and 13E are diagrams illustrating examples ofindexes of RUs available in a 320 MHz OFDMA PPDU;

FIG. 14 is a view illustrating a structure of a trigger frame;

FIG. 15 is a diagram illustrating an example of a common informationfield;

FIGS. 16A and 16B are diagrams illustrating respective examples of auser information field;

FIG. 17 is a message flow diagram illustrating a method of communicationbased on an extended bandwidth and a multi-RU according to anembodiment;

FIG. 18 shows small-size multi-RUs allocable to a STA in an OFDMA 20 MHzEHT PPDU according to an embodiment;

FIG. 19 shows small-size multi-RUs allocable to a STA in an OFDMA 40 MHzEHT PPDU according to an embodiment;

FIG. 20 shows small-size multi-RUs allocable to a STA in an OFDMA 80 MHzEHT PPDU according to an embodiment;

FIGS. 21A and 21B show small-size multi-RUs allocable to a STA in anOFDMA 160 MHz EHT PPDU according to an embodiment;

FIGS. 22A, 22B, and 22C show small-size multi-RUs allocable to a STA inan OFDMA 320 MHz EHT PPDU according to an embodiment;

FIG. 23 shows large-size multi-RUs allocable to a STA in an OFDMA 80 MHzEHT PPDU according to an embodiment;

FIG. 24 shows large-size multi-RUs allocable to a STA in an OFDMA 160MHz EHT PPDU according to an embodiment;

FIGS. 25A, 25B, and 25C show large-size multi-RUs allocable to a STA inan OFDMA 320 MHz EHT PPDU according to an embodiment;

FIG. 26 is a flowchart illustrating a method of communication based onan extended bandwidth and a multi-RU according to an embodiment;

FIG. 27 is a flowchart illustrating a method of communication based onan extended bandwidth and a multi-RU according to an embodiment;

FIGS. 28A and 28B are diagrams illustrating examples of a userinformation field according to example embodiments;

FIGS. 29A and 29B are diagrams illustrating an RU allocation subfieldaccording to an embodiment;

FIG. 30 shows values of multi-RUs including a 996-tone RU and a 484-toneRU and an RU allocation subfield according to an embodiment;

FIG. 31 shows values of multi-RUs including a 996-tone RU, a 484-toneRU, and a 242-tone RU and an RU allocation subfield according to anembodiment;

FIG. 32 shows values of multi-RUs including two 996-tone RUs and484-tone RUs and an RU allocation subfield according to an embodiment;

FIG. 33 shows values of multi-RUs including three 996-tone RUs and an RUallocation subfield according to an embodiment;

FIG. 34 shows values of multi-RUs including three 996-tone RUs and484-tone RUs and an RU allocation subfield according to an embodiment;and

FIG. 35 is a diagram illustrating an RU allocation subfield according toan embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the inventive concept will be described indetail with reference to the accompanying drawings.

Terms used herein are for describing embodiments and are not forlimiting the inventive concept. Herein, a singular form includes aplural form unless specially described. Described components, processes,operations and/or elements do not exclude the presence or addition ofone or more other components, processes, operations and/or elements.

Unless otherwise defined, all the terms (including technological andscientific terms) used herein may be used in the meaning that may becommonly understood by those skilled in the art. In addition, termsdefined in a commonly used dictionary are not ideologically orexcessively interpreted unless specially defined.

In addition, in specifically describing the embodiments of the inventiveconcept, OFDM or an OFDM-based wireless communication system, inparticular, the IEEE 802.11 standard is to be mainly described. However,the inventive concept may also be applied to other communication systemswith a similar technological background and channel type (for example, acellular communication system such as long term evolution (LTE),LTE-Advanced (LTE-A), new radio (NR)/5G, wireless broadband (WiBro), orglobal system for mobile communication (GSM) or a remote communicationsystem such as Bluetooth or near field communication (NFC).

Herein, the term “connects (combines)” and derivatives thereof refer todirect or indirect communication between two or more components thatphysically contact or do not physically contact. The terms “transmits”,“receives”, and “communicates” and derivatives thereof include alldirect and indirect communication. “Comprises” and/or “comprising” usedherein mean inclusion without limit. “Or” is a collective term meaning‘and/or’. “Is related to ˜” and derivatives thereof mean includes, isincluded in ˜, is connected to ˜, implies, is implied in ˜, is connectedto ˜, is combined with ˜, may communicate with ˜, cooperates with ˜,interposes, puts in parallel, is close to ˜, is bound to ˜, has, has afeature of ˜, and has a relation with ˜. “A controller” means a certaindevice, system, or a part thereof controlling at least one operation.The controller may be implemented by hardware or a combination ofhardware and software and/or firmware. A function related to a specificcontroller may be locally or remotely concentrated or dispersed.

In addition, various functions described hereinafter may be implementedor supported by one or more computer programs and each of the programsis formed of computer-readable program code and is executed in acomputer-readable recording medium. “An application” and “a program”refer to one or more computer programs, software components, instructionsets, processes, functions, objects, classes, instances, related data,or parts thereof suitable for implementation of pieces ofcomputer-readable program code. “Computer-readable program code” includeall types of computer code including source code, object code, andexecution code. “Computer-readable media” include all types of mediathat may be accessed by a computer such as read only memory (ROM),random access memory (RAM), a hard disk drive, a compact disk (CD), adigital video disk (DVD), and other types of memory. “Non-transitory”computer-readable media exclude wired, wireless, optical, or othercommunication links transmitting temporary electrical or other signals.Non-transitory computer-readable media include a medium in which datamay be permanently stored and a medium in which data may be stored andmay be overwritten later such as a rewritable optical disk or adeletable memory device.

Herein, the terms “subcarrier” and “tone” may be used interchangeably,and a “size of an RU” means a number of tones of an RU.

Herein, a “leftmost side of a band” refers to a range of frequencieswithin the band starting at the lowest frequency within the band.

FIG. 1 is a view illustrating a wireless local area network (WLAN)system 100. FIG. 2 is a block diagram illustrating a wirelesscommunication device 1100 transmitting or receiving a physical layerconvergence protocol (PLCP) protocol data unit (PPDU). As illustrated inFIG. 1 , the WLAN system 100 may include access points (AP) 101 and 103.The APs 101 and 103 may communicate with at least one network 130 suchas the Internet, an internet protocol (IP) network, or a private datanetwork.

The APs 101 and 103 may provide wireless connection to the network 130for a plurality of stations (STAs) 111 to 114 in coverage areas 120 and125 thereof. The APs 101 and 103 may communicate with each other andwith the STAs 111 to 114 by using WiFi or other WLAN communicationtechnologies. Herein, AP may be referred to as a first device or atransmitting device, and STA may be referred to as a second device or areceiving device.

For example, in accordance with a network type, other well-known termssuch as “a router” and “a gateway” may be used instead of “the AP”. Inaddition, in the WLAN, the AP is provided for a wireless channel. An APmay operate as a STA in some scenarios, such as when a first APcommunicates with a second AP, and the second AP operates as a STA basedon control information provided by the first AP.

In addition, in accordance with the network type, “STA” may be usedinstead of other well-known terms such as “a mobile station”, “asubscriber station”, “a remote terminal”, “user equipment”, “a wirelessterminal”, “a user device”, or “a user”. For convenience, herein, “STA”is used for representing a remote wireless device wirelessly connectedto the AP or connected to the wireless channel in the WLAN. Herein, aSTA is considered as a mobile device (e.g., a mobile telephone or asmartphone). In other examples, a STA is a fixed device (e.g., a desktopcomputer, the AP, a media player, a fixed sensor, or a television set).

Approximate extents of the coverage areas 120 and 125 are marked withdashed lines. Here, the coverage areas 120 and 125 are illustrated asbeing circular for simplicity of explanation. However, each of thecoverage areas 120 and 125 related to the APs 101 and 103 may haveanother shape to which a varying change in wireless environment relatedto a natural or artificial obstruction is reflected or another irregularshape in accordance with setting of the APs 101 and 103.

As described in detail later, the APs 101 and 103 may include circuitryand/or a program for managing transmission of an uplink multiuser (ULMU)or a downlink multiuser (DLMU) in the WLAN system 100.

In other examples, the WLAN system 100 may include an arbitrary numberof properly arranged APs and an arbitrary number of STAs. In addition,the AP 101 may directly communicate with an arbitrary number of STAs.The AP 101 may provide wireless broadband access to the plurality ofSTAs 111 to 114 via the network 130.

Similarly, each of the APs 101 and 103 may directly communicate with thenetwork 130 and may provide wireless broadband access to the pluralityof STAs 111 to 114 via the network 130. In addition, the APs 101 and 103may be configured to connect to a varying external network such as anexternal telephone network or a data network.

As depicted in FIG. 2 , a wireless communication device transmitting orreceiving the PPDU is illustrated. For example, the wirelesscommunication device 1100 of FIG. 2 may be a transmission device (e.g.,an AP) or a receiving device (e.g., a STA) with a transceiver capable ofperforming data communication. That is, the wireless communicationdevice 1100 of FIG. 2 may be one of the APs 101 and 103 and theplurality of STAs 111 to 114 illustrated in FIG. 1 and may be applied toa sensor used for, for example, a computer, a smartphone, a portableelectronic device, a tablet, a wearable device, or an Internet of Things(IoT). In the following description, a STA is an example of a “receivingdevice”. Moreover, the terms “user” and “STA” may be usedinterchangeably. Further, an AP is an example of a “transmitting device”in the following description.

For ease of explanation, hereinafter, a case in which the wirelesscommunication device 1100 is the transmission device is taken as anexample.

The wireless communication device 1100 may include a main processor1130, memory 1120, a transceiver 1140, and antenna arrays 1101 to 1104.The main processor 1130, the memory 1120, the transceiver 1140, and theantenna arrays 1101 to 1104 may be directly or indirectly connected toeach other.

The main processor 1130 may control the memory 1120 and the transceiver1140. A PPDU format and multiple resource unit (RU) allocationinformation may be stored in the memory 1120. The transceiver 1140 maygenerate the PPDU by using the PPDU format and the multiple RUallocation information stored in the memory 1120. The transceiver 1140may transmit the generated PPDU to an external receiving device throughthe antenna arrays 1101 to 1104.

Here, the memory 1120 may store a PPDU format 1121 including a RUallocation signaling format according to an embodiment of the inventiveconcept, which will be described later. The memory 1120 may storeprocessor-executable instructions executing a RU allocation module 1122and a PPDU generation module 1123. The processor-executable instructionsmay be executed by the main processor 1130, in which case circuitry ofthe main processor 1130 performs the functions of the RU allocationmodule 1122 and the PPDU generation module 1123; accordingly, thesemodules may interchangeably be called RU allocation circuitry 1122 andPPDU generation circuitry, respectively.

For example, the RU allocation module 1122 may use an RU allocationalgorithm, method, or policy to allocate at least one RU (e.g., a singleRU or a multiple RU) to a user according to an embodiment of theinventive concept. The PPDU generation module 1123 may generatesignaling and indication related to allocation of the at least one RU ina trigger frame of the PPDU.

On the other hand, the transceiver 1140 may include a signal processor1150. The signal processor 1150 may include various transmission pathmodules generating sections of the PPDU or various types ofcommunication transmission units.

The signal processor 1150 may include a transmit first-in-first-out (TXFIFO) 1111, an encoder 1112, a scrambler 1113, an interleaver 1114, aconstellation mapper 1115 capable of, for example, generating a QAMsymbol, a guard interval and windowing insertion module 1116 capable of,for example, providing a guard interval on a frequency to reduceinterference on a spectrum and transforming a signal through windowing,and an inversed discrete Fourier transformer (IDFT) 1117.

It is noted that the transceiver 1140 may include parts well-known tothose skilled in the art as illustrated in the drawing. Thecorresponding parts may be executed by a method well-known to thoseskilled in the art by using hardware, firmware, software logic, or acombination of hardware, firmware, and software logic.

When the wireless communication device 1100 is a receiving device, thetransceiver 1140 illustrated in FIG. 2 may include components in areceiving path.

That is, when the wireless communication device 1100 is a receivingdevice, the transceiver 1140 may receive the PPDU including a triggerframe from the transmission device. The transceiver 1140 may decode thetrigger frame included in the received PPDU. That is, the transceiver1140 may identify an RU allocated for the receiving device by decodingthe trigger frame through an internal decoder (not shown), decode thetrigger frame, identify at least one RU allocated to uplink bandwidthand the receiving device and transmit PPDU to the transmitting devicebased on the identified at least one RU. Alternatively, the decoding maybe performed by a component other than the transceiver 1140, e.g., themain processor 1130.

Hereinafter, high efficiency (HE) PPDUs used in the institute ofelectrical and electronics engineers (IEEE) standard (that is, 802.11ax)will be described with reference to FIGS. 3 to 6 . For example, the HEPPDUs described with reference to FIGS. 3 to 15 may be generated by thewireless communication device 1100 of FIG. 2 .

FIG. 3 is a view illustrating a structure of an HE single user (SU)PPDU. FIG. 4 is a view illustrating a structure of an HE extended range(ER) SU PPDU. FIG. 5 is a view illustrating a structure of an HE triggerbased (TB) PPDU. FIG. 6 is a view illustrating a structure of an HEmultiuser (MU) PPDU. As illustrated in FIGS. 3 to 6 , each HE PPDU mayinclude a preamble including a plurality of training fields and aplurality of signaling fields and a payload including a data (DATA)field and a packet extension (PE) field.

Each HE PPDU may include a legacy-short training field (L-STF) with alength of 8 us, a legacy-long training field (L-LTF) with a length of 8us, a legacy-signal (L-SIG) field with a length of 4 us, a repeatedL-SIG (RL-SIG) field with a length of 4 us, a high efficiency-signal-A(HE-SIG-A) field with a length of 8 us, an HE-STF with a length of 4 us,an HE-LTF, a DATA field, and a PE field.

The HE SU PPDU of FIG. 3 does not include an HE-SIG-B field, and the HEMU PPDU of FIG. 6 may further include the HE-SIG-B field. The HE ER SUPPDU of FIG. 4 does not include the HE-SIG-B field. However, a symbol ofthe HE-SIG-A field may be repeated with a length of 16 us. In addition,the HE TB PPDU of FIG. 5 does not include the HE-SIG-B field. However, asymbol of the HE-STF may be repeated with a length of 8 us.

Here, the fields included in the preamble will be simply described asfollows.

The L-STF may include a short training orthogonal frequency divisionmultiplexing (OFDM) symbol and may be used for frame detection,automatic gain control (AGC), diversity detection, and coarsefrequency/time synchronization.

The L-LTF may include a long training OFDM symbol and may be used forfine frequency/time synchronization and channel estimation.

The L-SIG field may be used for transmitting control information and mayinclude information on a data rate and a data length. For example, theL-SIG field may be repeatedly transmitted. A format in which the L-SIGfield is repeated is referred to as the RL-SIG field.

The HE-SIG-A field may include control information common to thereceiving device, which is as follows.

-   -   1) a downlink (DL)/uplink (UL) indicator    -   2) a basic service set (BSS) color field that is an identifier        of a BSS    -   3) a field indicating a remaining time of a current transmission        opportunity (TXOP) period    -   4) a bandwidth field indicating 20/40/80/160/80+80 MHz    -   5) a field indicating a modulation and coding scheme (MCS)        applied to the HE-SIG-B field    -   6) a field indicating whether the HE-SIG-B field is modulated by        a dual subcarrier modulation scheme    -   7) a field indicating the number of symbols used for the        HE-SIG-B field    -   8) a field indicating whether the HE-SIG-B field is generated        over the entire band    -   9) a field v the number of symbols of the HE-LTF    -   10) a field indicating a length of the HE-LTF and a length of a        cyclic prefix (CP) field    -   11) a field indicating whether an additional OFDM symbol is        provided for low density parity check (LDPC) coding    -   12) a field indicating control information on the PE field    -   13) a field indicating information on a cyclical redundancy        check (CRC) field of the HE-SIG-A field

The HE-SIG-A field may further include various information items otherthan the above-described 1) to 13) or may not include partialinformation items among the above-described 1) to 13). In environmentsother than an MU environment, partial information items may be furtheradded to the HE-SIG-A field or partial information items of the HE-SIG-Afield may be omitted.

The HE-SIG-B field may be used for the PPDU for the MU. Thus, theHE-SIG-B field may be omitted from the PPDU for the SU. For example,because the HE-SIG-A field or the HE-SIG-B field may include RUallocation information on at least one receiving device for downlinktransmission. The PE field may have duration of 4 □s, 8 □s, 12 □s, or 16□s and may provide an additional receive processing time at an end ofthe HE PPDU.

FIG. 7 is a view illustrating a structure of an EHT TB PPDU. FIG. 8 is aview illustrating a structure of an EHT MU PPDU. An embodiment of theinventive concept may also be applied to 802.11be, which is a nextgeneration WLAN standard. Therefore, because the method and theapparatus for allocating the RU according to an embodiment of theinventive concept may be implemented in signaling fields (for example,extremely high throughout (EHT)-SIG fields) of EHT PPDUs, hereinafter,with reference to FIGS. 18 and 19 , the EHT PPDUs used in the IEEEstandard (that is, 802.11be) will be described. For reference, the EHTPPDUs described with reference to FIGS. 7 and 8 may be generated by thewireless communication device 1100 of FIG. 2 .

As illustrated in FIGS. 7 and 8 , each EHT PPDU may include a preambleincluding a plurality of training fields and a plurality of signalingfields and a payload including a data field.

Each EHT PPDU may include an L-STF with a length of 8 us, an L-LTF witha length of 8 us, an L-SIG field with a length of 4 us, a repeated L-SIG(RL-SIG) field with a length of 4 us, a universal-signal (U-SIG) fieldwith a length of 8 us, an EHT-STF, an EHT-LTF, and a DATA field.

The EHT TB PPDU of FIG. 7 does not include an EHT-SIG field. However, asymbol of the EHT-STF may be repeated. The EHT MU PPDU of FIG. 8 mayconsist of a plurality of OFDM symbols and may further include theEHT-SIG field. In addition, like the above-described HE TB PPDU of FIG.5 , the EHT TB PPDU of FIG. 7 may require a trigger frame to transmitthe EHT TB PPDU. The trigger frame for transmitting the EHT TB PPDU mayhave a structure and a function similar to those of a trigger frame ofFIG. 14 described later.

For example, a PE field may be further included in each EHT PPDU. Thefigures herein, however, illustrate EHT PPDUs without PE field.

Fields included in each EHT PPDU will be simply described as follows.

Because ‘the L-STF’, ‘the L-LTF’, ‘the L-SIG field’, and ‘the RL-SIGfield’ of each EHT PPDU are the same as or similar to ‘the L-STF’, ‘theL-LTF’, ‘the L-SIG field’, and ‘the RL-SIG field’ of the above-describedHE PPDU, detailed description thereof will be omitted.

The U-SIG field performing a function similar to that of the HE-SIG-Afield of the HE PPDU may be arranged immediately next to the RL-SIGfield and may include commonly encoded two OFDM symbols.

The U-SIG field may include ‘version-independent fields’ and‘version-dependent fields’ and ‘the version-dependent fields’ may bearranged next to ‘the version-independent fields’.

Here, ‘the version-independent fields’ may have static location and bitdefinition over different generations/physical versions.

In addition, ‘the version-independent fields’ may include, for example,next control information, as follows:

-   -   1) a PHY version identifier (consisting of three bits)    -   2) an uplink (UL)/downlink (DL) flag (consisting of one bit)    -   3) a BSS color field that is an identifier of a BSS    -   4) a TXOP duration (that is, a field indicating a remaining time        of a current TXOP period)    -   5) a bandwidth field (that may carry partial “puncturing”        information, where a “punctured” subset of frequencies within        the bandwidth field are frequencies that are not used.        Puncturing of frequencies may typically be implemented to avoid        interference with another AP using the frequencies.).

On the other hand, ‘the version-dependent fields’ may have variable bitdefinition in each PHY version.

In addition, ‘the version-dependent fields’ may include, for example,next control information as follows:

-   -   1) a PPDU type (a field indicating the PPDU type)    -   2) an EHT-SIG modulation and coding scheme (MCS) (a field        indicating the MCS and provided in the U-SIG field of the EHT        PPDU, which is transmitted to the MU)    -   3) the number of EHT-SIG symbols (a field indicating the number        of symbols used for the EHT-SIG field and provided in the U-SIG        field of the EHT PPDU, which is transmitted to the MU).

The U-SIG field may further include various information items other thanthe above-described control information or may not include partialinformation among the above-described control information items. Inenvironments other than an MU environment, partial information may befurther added to the U-SIG field or partial information of the U-SIGfield may be omitted.

The EHT-SIG field performing a function similar to that of the HE-SIG-Bfield of the HE PPDU may be arranged immediately next to the U-SIG fieldin the EHT PPDU, which is transmitted to the MU, and may have a variableMCS and a variable length.

The EHT-SIG field may include a common field including common controlinformation and a user-specific field including user-specific controlinformation.

Here, the common field may be encoded apart from the user-specificfield. In addition, the common field may include RU allocation relatedinformation for downlink transmission (for example, informationincluding ‘an RU allocation subfield’ and ‘an additional RU allocationsubfield’, which is described later) and the user-specific field mayinclude information (that is, user information allocated for each RU)similar to information included in the user-specific field of theabove-described HE-SIG-B field.

For example, in the common field of the EHT-SIG field of the EHT PPDU,which is transmitted to the MU, at least one compression mode in which‘the RU allocation subfield’ is not provided may be provided. Inaddition, the EHT-SIG field may be basically used for the PPDU for theMU. However, unlike in ‘the HE PPDU’, when an overhead of the U-SIGfield increases, the EHT-SIG field may be used for the PPDU fortransmitting the SU.

FIGS. 9A and 9B are diagrams illustrating examples of RU available in a20 MHz OFDMA PPDU and indexes thereof; FIGS. 10A and 10B are diagramsillustrating examples of RU available in a 40 MHz OFDMA PPDU and indexesthereof; FIGS. 11A and 11B are diagrams illustrating examples of RUavailable in an 80 MHz OFDMA PPDU and indexes thereof; FIGS. 12A and 12Bare diagrams illustrating examples of indexes of RU available in a 160MHz OFDMA PPDU. FIGS. 13A, 13B, 13C, 13D, and 13E are diagramsillustrating examples of indexes of RU available in a 320 MHz OFDMAPPDU. That is, as illustrated in FIGS. 9A, 10A and 11A, at least one RUmay be arranged in the frequency domain of the data field (thehorizontal axis of each of FIGS. 9A, 10A and 11A represents thefrequency domain). In FIGS. 9B, 10B, 11B, 12A, 12B, 13A, 13B, 13C, 13Dand 13E, a zero index of subcarrier may correspond to a DC-tone, anegative index of subcarrier may correspond to a subcarrier having afrequency lower than the DC-tone, and a positive index of subcarrier maycorrespond to a subcarrier having a frequency higher than the DC-tone.

First, in FIG. 9A, the arrangement of the RU available in the 20 MHzOFDMA PPDU is illustrated. In the leftmost band of a 20 MHz band, sixtones (that is, subcarriers) may be used as a guard band and, in therightmost band of the 20 MHz band, five tones may be used as a guardband. In addition, 26-tone RUs, 52-tone RUs, and 106-tone RUs may beallocated for other bands. Seven direct current (DC) tones may beinserted into a central band, that is, a DC band and a 26-tone RUcorresponding to 13 tones may be provided on each of left and rightsides of the DC band. Each RU may be allocated for a receiving device,that is, a user.

For example, the RU arrangement of FIG. 9A may be used for a situationfor an SU as well as a situation for a MU. Therefore, as illustrated inthe uppermost portion of FIG. 9A, a plurality of 26-tone RUs may bearranged and, as illustrated in the lowermost portion of FIG. 9A, one242-tone RU including 242L and 242R may be arranged (in this case, threeDC tones may be inserted into the central band).

Various sizes of RUs, that is, the 26-tone RUs, the 52-tone RUs, the106-tone RUs, and the 242-tone RU are suggested in an example of FIG.9A. In other examples, the sizes of the RUs may differ.

Referring to FIG. 9B, RUs in FIG. 9A may be indexed sequentially fromthe lowest frequency. For example, the 26-tone RU may be indexed asfirst to ninth RUs RU1 to RU9, the 52-tone RU may be indexed as first tofourth RUs RU1 to RU4, the 106-tone RU may be indexed as first andsecond RUs RU1 and RU2, and 242-tone RU may be indexed as a first RURU1. A fifth RU is a central 26-tone RU in FIG. 9B.

As shown in FIG. 10A, the arrangement of the RU available in the 40 MHzOFDMA PPDU is illustrated. In the leftmost band of a 40 MHz band, 12tones (that is, subcarriers) may be used as a guard band and, in therightmost band of the 40 MHz band, 11 tones may be used as a guard band.In addition, five DC tones may be inserted into a central band, that is,a DC band. In addition, 26-tone RUs, 52-tone RUs, 106-tone RUs, and242-tone RUs may be allocated for other bands. Each RU may be allocatedfor a receiving device, that is, a user.

Note that the RU arrangement of FIG. 10A may be used for a situation fora SU as well as a situation for a MU. Therefore, as illustrated in thelowermost portion of FIG. 10 , one 484-tone RU including 484L and 484Rmay be arranged (in this case, five DC tones may be inserted into thecentral band).

Various sizes of RUs, that is, the 26-tone RUs, the 52-tone RUs, the106-tone RUs, the 242-tone RUs, and the 484-tone RU are suggested in anexample of FIG. 10A. In other examples, the sizes of the RUs may differ.

Referring to FIG. 10B, RUs in FIG. 10A may be indexed sequentially fromthe lowest frequency. For example, the 26-tone RU may be indexed asfirst to 18th RUs RU1 to RU18, the 52-tone RU may be indexed as first toeighth RUs RU1 to RU8, the 106-tone RU may be indexed as first to fourthRUs RU1 to RU4, the 242-tone RU may be indexed as first and second RUsRU1 and RU2, and the 484-tone RU may be indexed as a first RU RU1.

In FIG. 11A, the arrangement of the RU available in the 80 MHz OFDMAPPDU is illustrated.

Specifically, in the leftmost band of an 80 MHz band, 12 tones (that is,subcarriers) may be used as a guard band and, in the rightmost band ofthe 80 MHz band, 11 tones may be used as a guard band. In addition,26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, and 484-tone RUsmay be allocated for other bands. Each RU may be allocated for areceiving device, that is, a user.

The RU arrangement of FIG. 11A may be used for a situation involving anSU as well as one involving an MU. Therefore, as illustrated in thelowermost portion of FIG. 11A, one 996-tone RU including 996L and 996Rmay be arranged (in this case, five DC tones may be inserted into thecentral band).

Various sizes of RUs, that is, the 26-tone RU (“RU26”), the 52-tone RU(“RU52”), the 106-tone RU (“RU106”), the 242-tone RU (“RU242”), the484-tone RU (“RU484”), and the 996-tone RU (“RU996”) are suggested in anexample of FIG. 11A. However, the RU sizes may differ in otherembodiments.

Referring to FIG. 11B, RUs in FIG. 11A may be indexed sequentially fromthe lowest frequency. For example, the 26-tone RU may be indexed asfirst to 37th RUs RU1 to RU37, the 52-tone RU may be indexed as first to16th RUs RU1 to RU16, the 106-tone RU may be indexed as first to eighthRUs RU1 to RU8, the 242-tone RU may be indexed first to fourth RUs RU1to RU4, the 484-tone RU may be indexed as first and second RUs RU1 andRU2, and the 996-tone RU may be indexed as a first RU RU1. The central26-tone RU may be used in HE (i.e., 802.11ax) but may not be used in EHT(i.e., 802.11be). In some embodiments, as illustrated in FIG. 11B, Thecentral 26-tone RU may be indexed as a 19th RU RU19. Accordingly, anindexing of RU in EHT may be compatible with an indexing of RU in HE.

Referring FIGS. 12A and 12B, RUs in 160 MHz OFDM PPDU may be indexedsequentially from the lowest frequency. For example, the 26-tone RU maybe indexed as first to 74th RUs RU1 to RU74. As described with referenceto FIG. 11B, the central 26-tone RU in 20 MHz bandwidth may not be used.Accordingly, the 19th RU RU19 and the 56th RU RU56 may not be used.

Referring to FIGS. 13A, 13B, 13C, 13D and 13E, RUs in 320 MHz bandwidthmay be indexed sequentially from the lowest frequency. For example, the26-tone RU may be indexed as first to 148th RUs RU1 to RU148. Asdescribed with reference to FIG. 11B, the central 26-tone RU in 20 MHzbandwidth. Accordingly, the 19th RU RU19, the 56th RU RU56 and the 93thRU RU93 in FIGS. 13A and 13B may not be used.

In some embodiments, RU positions available in the 40 MHz OFDMA PPDU arethe same as two replicas of RU positions available in the 20 MHz OFDMAPPDU. In addition, RU positions available in the 80 MHz OFDMA PPDU maybe the same as two replicas of the RU positions available in the 40 MHzOFDMA PPDU. In addition, RU positions available in the 160 MHz OFDMAPPDU may be the same as two replicas of the RU positions available inthe 80 MHz OFDMA PPDU. In addition, RU positions available in the 320MHz OFDMA PPDU may be the same as two replicas of the RU positionsavailable in the 160 MHz OFDMA PPDU. Accordingly, in 160MH bandwidth,the 52-tone RU may be indexed as first to 32th RUs RU1 to RU32, the106-tone RU may be indexed as first to 16th RUs RU1 to RU16, the242-tone RU may be indexed as first to 8 RUs RU1 to RU8, the 484-tone RUmay be indexed as first to fourth RUs RU1 to RU4, and the 996-tone RUmay be indexed as first and second RUs RU1 and RU2. Similarly, in 320MHz bandwidth, the 52-tone RU may be indexed as first to 64 RUs RU1 toRU64, the 106-tone RU may be indexed as first to 32 RUs RU1 to RU32, the242-tone RU may be indexed a s first to 16th RUs RU1 to RU16, the484-tone RU may be indexed as first to eighth RUs RU1 to RU8, and the996-tone RU may be indexed as first to fourth RUs RU1 to RU4.

As described above, at least one RU may be variously arranged in afrequency domain of a data field.

FIG. 14 is a view illustrating a structure of a trigger frame. Forexample, when a UL transmission is to be performed by one or more STAsto an AP, the AP may allocate different frequency resources for the oneor more STAs as UL transmission resources based on OFDMA. Here, anexample of the frequency resource is an RU, which may be indicated by atrigger frame transmitted by the AP to the STA before the ULtransmission.

Therefore, to transmit the HE TB PPDU of FIG. 5 or EHT TB PPDU of FIG. 7, a trigger frame as illustrated in FIG. 14 is first transmitted to theSTA. The trigger frame may set uplink bandwidth and allocate the RU forUL multiple-user transmission. The trigger frame may be formed of a MAC(media access control) frame and may be included in a PPDU.

The trigger frame may be transmitted through the PPDU illustrated inFIGS. 3 to 8 or a PPDU specially designed for the corresponding triggerframe. For example, when the trigger frame is transmitted through thePPDU illustrated in FIGS. 3 to 8 , the trigger frame may be included inthe data field.

As illustrated in FIG. 14 , a trigger frame may include a frame controlfield 400 (2 octets), a duration field 405 (2 octets), an RA (recipientaddress) field 410 (6 octets), a TA (transmitting address) field 415 (6octets), a common information field 420 (no less than 8 octets),individual user information fields 425-1 to 425-N (N is a natural numberof 1 or more, and each information field is 5 or more octets), a paddingfield 430, and a frame check sequence (FCS) field 435 (no less than 4octets).

The frame control field 400 may include information on a version of aMAC protocol and other additional control information items. Theduration field 405 may include time information for setting a networkallocation vector (NAV) or information on an identifier (e.g., anassociation ID (AID)) of a terminal. The RA field 410 may includeaddress information of the receiving device of the corresponding triggerframe and may be omitted when unnecessary. The TA field 415 may includeaddress information of a transmitting device transmitting thecorresponding trigger frame.

In the TA field 415, a field indicating a length of an L-SIG field of aUL PPDU transmitted to the corresponding trigger frame or informationcontrolling a content of an SIG-A field (that is, the HE-SIG-A field) ofthe UL PPDU transmitted to the corresponding trigger frame may beincluded. In addition, in the TA field 415, as common controlinformation, information on a length of a CP of the UL PPDU transmittedto the corresponding trigger frame or information on a length of an LTFfield may be included.

The common information field 420 may include common information forreceiving devices (for example, STA) receiving the corresponding triggerframe. The trigger frame may include the individual user informationfields 425-1 to 425-N (N is a natural number of no less than 1)corresponding to the number of receiving devices receiving the triggerframe. For reference, the individual user information fields may bereferred to as “user info list field”. The trigger frame may include thepadding field 430 and the FCS field 435.

In other examples, some fields of the trigger frame may be omitted andother fields may be added. Further, a length of each field may bedifferent from those illustrated.

An embodiment of the inventive concept relates to a method and apparatusfor supporting MU communication using OFDMA. APs may allocate at leastone RU for at least one of a plurality of receiving devices (e.g., STAs)through the OFDMA in an extended bandwidth. A method and apparatus forproviding a trigger frame including information about an uplinkbandwidth and at least one RU allocated the receiving device will bedescribed later. In addition, a method and apparatus for identifying theuplink bandwidth and the allocated at least one RU from the triggerframe will be described. For example, as described later with referenceto FIG. 17 , the AP may allocate at least one RU to at least one STA,generate a trigger frame for uplink transmission, and transmit thegenerated trigger frame to the at least one STA. The STA may receive thetrigger frame from the AP, identify at least one RU allocated to the STAfor uplink OFDMA, transmit data, e.g., a PPDU, to the AP based on theidentified at least one RU. However, an embodiment of the inventiveconcept may be applied to a case where the STA transmits data to anotherSTA and a case where the AP transmits data to the STA. In addition, anembodiment of the inventive concept may be applied to a circumstancesupporting a single RU as well as downlink OFDMA and uplink OFDMA.Information about uplink bandwidth and RU allocated to the receivingdevice may be provided to the receiving device by the common info field420 and the user info field of the trigger frame. Hereinafter, thecommon info field 420 and the user info field will be described withreference to FIGS. 15, 16A and 16B.

FIG. 15 is a diagram illustrating an example of a common informationfield, which contains information commonly applicable to multiple STAs.FIGS. 16A and 16B are diagrams illustrating respective examples of auser information field.

Referring to FIG. 15 , the common information field may include asequence of subfields from a first subfield 151 to a last subfield 168.A STA may set a value of an uplink bandwidth subfield 420_1 among theplurality of subfields included in the common information field, and theSTA may identify an uplink bandwidth based on the value of the uplinkbandwidth subfield 420_1. The uplink bandwidth subfield 420_1 may have alength L1 for defining various uplink bandwidths. For example, a lengthL1 of the uplink bandwidth subfield 420_1 in HE may be 2 bits toindicate one of 20 MHz, 40 MHz, 80 MHz, and 160 MHz. In EHT, the lengthL1 of the uplink bandwidth subfield 420_1 may be at least 3 bits toindicate one of four bandwidths supported by the HE as well as anextended bandwidth, e.g., bandwidths up to 320 MHz. Herein, the uplinkbandwidth may be simply referred to as a bandwidth unless otherwisestated. In other examples, the common information field includes afield(s) not shown in FIG. 15 , and/or at least one field shown in FIG.15 may be omitted from the common information field.

Referring to FIG. 16A, a first example of a user information field mayinclude subfields such as an AID12 field 425_1 a and an RU allocationsubfield 425_2 a. To specify the STA, an AP may set a value of the AID12field 425_1 a, and the STA may identify that the user information fieldis the user information field of the STA based on the value of the AID12field 425_1 a. In addition, to define at least one allocated RU, the APmay set a value of the RU allocation subfield 425_2 a, and the STA mayidentify the at least one RU, which is allocated to the STA, based onthe value of the RU allocation subfield 425_2 a.

The RU allocation subfield 425_2 a may have a length L2 a for definingvarious RU allocations. For example, the length L2 a of the RUallocation subfield 425_2 a in the HE may be 8 bits to indicate a singleRU allocable to the STA within a bandwidth of up to 160 MHz. However, inEHT, the RU allocation subfield 425_2 a may indicate not only the singleRU allocable to the STA within the bandwidth of up to 320 MHz, but alsoa multi-RU, and accordingly, a length of an RU allocation subfield 426_2a may be longer than at least 8 bits. The RU allocation subfield 425_2 afor EHT may have a length of 9 bits, as will be described later withreference to FIG. 28A.

Referring to FIG. 16B, the user information field may include aplurality of subfields including an AID12 field 425_1 b and an RUallocation subfield 425_2 b. In addition, the user information field mayfurther include a PS160 subfield 425_3 indicating a primary subband or asecondary subband, as shown in FIG. 16B. Although the PS160 subfield425_3 is shown in FIG. 16B to correspond to a reserved area (e.g., B39)of the user information field of FIG. 16A, in other examples, the PS160subfield 425_3 may be disposed in a different position from that shownin FIG. 16B.

As will be described later with reference to FIG. 28B, the PS160subfield 425_3 may be used to define various RU allocations togetherwith the RU allocation subfield 425_2 b, and accordingly, a length L2 bof the RU allocation subfield 425_2 b may be shorter than the length L2a of FIG. 16A. For example, the length L2 b of the RU allocationsubfield 425_2 b may be 8 bits. To define the at least one allocated RU,the AP may set values of the RU allocation subfield 425_2 b and thePS160 subfield 425_3, and the STA may identify the at least one RU,which is allocated to the STA, based on the values of the RU allocationsubfield 425_2 b and the PS160 subfield 425_3. FIG. 17 is a message flowdiagram illustrating a method of communication based on an extendedbandwidth and a multi-RU according to an embodiment. FIG. 17 showsexamples of operations of an AP 10 and a STA in communication with eachother. The AP 10 may communicate with at least one STA including the STA20 included in a coverage area.

Referring to FIG. 17 , in operation S10, the AP 10 may generate anuplink bandwidth field. For example, the AP 10 may determine a bandwidthto be used by at least one STA including the STA 20 in uplinktransmission. As described above with reference to FIG. 15 , in EHT, theuplink bandwidth field may have a length of at least 3 bits, and the AP10 may determine a bandwidth of one of 20 MHz, 40 MHz, 80 MHz, 160 MHz,and 320 MHz, and set the uplink bandwidth field to a value correspondingto the determined bandwidth.

In operation S20, the AP 10 may allocate at least one RU to the at leastone STA. For example, the AP 10 may allocate a single RU to the STA 20or may allocate a multi-RU to the STA 20. For EHT, AP 10 may allocate asingle RU to the STA 20 in the same way as is done in HE. Examples inwhich the AP 10 allocates a multi-RU to the STA 20 in a given bandwidthin EHT will be described later with reference to FIGS. 18 to 25C.

In operation S30, the AP 10 may generate at least one subfield. Forexample, the AP may generate at least one subfield included in a triggerframe based on the at least one RU allocated in operation S20. Asdescribed above with reference to FIG. 16A, an RU allocation subfield inEHT may have a length of at least 9 bits, and in operation S30, the AP10 may set the RU allocation subfield as a value corresponding to theallocated at least one RU. In other examples, as described above withreference to FIG. 16B, the RU allocation subfield in EHT may have alength of 8 bits, the user information field may include a PS160subfield, and in operation S30, the AP 10 may set the RU allocationsubfield and the PS160 subfield as values corresponding to the at leastone allocated RU. An example of operation S30 will be described laterwith reference to FIG. 26 .

In operation S40, the AP 10 may generate a trigger frame and a PPDU. Forexample, the AP 10 may generate a common information field including theuplink bandwidth field generated in operation S10 and a user informationfield including the at least one subfield generated in operation S30.The AP 10 may generate the trigger frame including the commoninformation field and the user information field, and may generate thePPDU including the trigger frame.

In operation S50, the AP 10 may transmit the PPDU, and the STA 20 mayreceive the PPDU. In operation S60, the STA 20 may extract the triggerframe. The STA 20 may extract the trigger frame from the PPDU receivedin operation S50.

In operation S70, the STA 20 may extract the uplink bandwidth field andthe at least one subfield. The STA 20 may extract the common informationfield and the user information field from the trigger frame extracted inoperation S60. The STA 20 may extract the uplink bandwidth field havinga length of at least 3 bits from the common information field, identifya user information field of the STA 20 based on an AID12 field, andextract the at least one subfield from the identified user informationfield.

In operation S80, the STA 20 may identify the at least one RU. The STA20 may identify the bandwidth based on the uplink bandwidth fieldextracted in operation S70, and identify the at least one RU, which isallocated to the STA 20, based on the identified bandwidth and the atleast one subfield extracted in operation S70. An example of operationS80 will be described later with reference to FIG. 27 .

In operation S90, the STA 20 may transmit the PPDU, and the AP 10 mayreceive the PPDU. The STA 20 may perform uplink transmission on the atleast one RU identified in operation S80 and may transmit the PPDU tothe STA 20. The AP 10 may receive the PPDU on the at least one RUallocated to the STA 20 within the bandwidth.

FIG. 18 shows small-size multi-RUs allocable to a STA in an OFDMA 20 MHzEHT PPDU according to an embodiment. Specifically, the table of FIG. 18shows indexes and combinations of the small-size multi-RUs allocable ina bandwidth of 20 MHz. As described later with reference to FIGS. 29Aand 29B, values of RU allocation subfields may increase in the order ofthe indexes shown in FIG. 18 . In FIG. 18 , the indexes of a single RUmay correspond to indexes shown in FIG. 9B.

Referring to FIG. 18 , the multi-RUs including a 52-tone RU and a26-tone RU may have three different combinations, and may be indexed asfirst to third multi-RUs MRU1 to MRU3. As shown in FIG. 18 , the firstmulti-RU MRU1 may include a second 52-tone RU and a second 26-tone RU,the second multi-RU MRU2 may include a second 52-tone RU and a fifth26-tone RU, and the third multi-RU MRU3 may include a third 52-tone RUand an eighth 26-tone RU.

A multi-RU including a 106-tone RU and a 26-tone RU may have twodifferent combinations, and may be indexed as the first and secondmulti-RUs MRU1 and MRU2. As shown in FIG. 18 , the first multi-RU MRU1may include a first 106-tone RU and a fifth 26-tone RU, and the secondmulti-RU MRU2 may include a second 106-tone RU and the fifth 26-tone RU.

FIG. 19 shows small-size multi-RUs allocable to a STA in an OFDMA 40 MHzEHT PPDU according to an embodiment. Specifically, the table of FIG. 19shows indexes and combinations of the small-size multi-RUs allocable ina bandwidth of 40 MHz. In some embodiments, as described later withreference to FIGS. 29A and 29B, values of RU allocation subfields mayincrease in the order of the indexes illustrated in FIG. 19 . In FIG. 19, the indexes of a single RU may correspond to the indices shown in FIG.10B.

Referring to FIG. 19 , the multi-RUs including a 52-tone RU and a26-tone RU may have six different combinations, and may be indexed asfirst to sixth multi-RUs MRU1 to MRU6. As shown in FIG. 19 , the firstmulti-RU MRU1 may include a second 52-tone RU and a second 26-tone RU,the second multi-RU MRU2 may include a second 52-tone RU and a fifth26-tone RU, the third multi-RU MRU3 may include a third 52-tone RU andan eighth 26-tone RU, the fourth multi-RU MRU4 may include a sixth52-tone RU and an 11th 26-tone RU, the fifth multi-RU MRU5 may include asixth 52-tone RU and a 14th 26-tone RU, and the sixth multi-RU MRU6 mayinclude a 7th 52-tone RU and a 17th 26-tone RU.

A multi-RU including a 106-tone RU and a 26-tone RU may have fourdifferent combinations, and may be indexed as the first to fourthmulti-RUs MRU1 to MRU4. As shown in FIG. 19 , the first multi-RU MRU1may include a first 106-tone RU and a fifth 26-tone RU, the secondmulti-RU MRU2 may include a second 106-tone RU and the fifth 26-tone RU,the third multi-RU MRU3 may include a third 106-tone RU and a 14th26-tone RU, and the fourth multi-RU MRU4 may include a fourth 106-toneRU and the 14th 26-tone RU.

FIG. 20 shows small-size multi-RUs allocable to a STA in an OFDMA 80 MHzEHT PPDU according to an embodiment. Specifically, the table of FIG. 20shows indexes and combinations of the small-size multi-RUs allocable ina bandwidth of 80 MHz. In some embodiments, as described later withreference to FIGS. 29A and 29B, values of RU allocation subfields mayincrease in the order of the indexes shown in FIG. 20 . In FIG. 20 , theindexes of a single RU may correspond to indices shown in FIG. 11B.

Referring to FIG. 20 , the multi-RUs including a 52-tone RU and a26-tone RU may have 12 different combinations, and may be indexed asfirst to twelfth multi-RUs MRU1 to MRU12. As shown in FIG. 20 , thefirst multi-RU MRU1 may include a second 52-tone RU and a second 26-toneRU, the second multi-RU MRU2 may include the second 52-tone RU and afifth 26-tone RU, the third multi-RU MRU3 may include a third 52-tone RUand an eighth 26-tone RU, the fourth multi-RU MRU4 may include a sixth52-tone RU and an 11th 26-tone RU, the fifth multi-RU MRU5 may includethe sixth 52-tone RU and a 14th 26-tone RU, and the sixth multi-RU MRU6may include a 7th 52-tone RU and a 17th 26-tone RU. In addition, theseventh multi-RU MRU7 may include a 10th 52-tone RU and a 21st 26-toneRU, the eighth multi-RU MRU8 may include the 10th 52-tone RU and a 24th26-tone RU, the ninth multi-RU MRU9 may include an 11th 52-tone RU and a27th 26-tone RU, the 10th multi-RU MRU10 may include a 14th 52-tone RUand a 30th 26-tone RU, the eleventh multi-RU MRU11 may include the 14th52-tone RU and a 33rd 26-tone RU, and the 12th multi-RU MRU6 may includea 15th 52-tone RU and a 36th 26-tone RU.

A multi-RU including a 106-tone RU and a 26-tone RU may have eightdifferent combinations, and may be indexed as the first to eighthmulti-RUs MRU1 to MRU8. As shown in FIG. 19 , the first multi-RU MRU1may include a first 106-tone RU and a fifth 26-tone RU, the secondmulti-RU MRU2 may include a second 106-tone RU and the fifth 26-tone RU,the third multi-RU MRU3 may include a third 106-tone RU and a 14th26-tone RU, and the fourth multi-RU MRU4 may include a fourth 106-toneRU and the 14th 26-tone RU. In addition, the fifth multi-RU MRU5 mayinclude a fifth 106-tone RU and a 24th 26-tone RU, the sixth multi-RUMRU6 may include a sixth 106-tone RU and the 24th 26-tone RU, theseventh multi-RU MRU7 may include a seventh 106-tone RU and a 33rd26-tone RU, and the eighth multi-RU MRU8 may include an eighth 106-toneRU and the 33rd 26-tone RU.

Like the multi-RUs including 52-tone RUs and 26-tone RUs and themulti-RUs including 106-tone RUs and 26-tone RUs, a multi-RU includingonly small-size RUs (i.e., a 26-tone RU, a 52-tone RU, and a 106-toneRU) may be referred to as a small-size multi-RU. In some embodiments,only some of the small-size multi-RUs may be used in a bandwidth equalto or greater than 80 MHz. For example, as shown in FIG. 20 , some(i.e., MRU1, MRU6, MRU7, and MRU12) of the multi-RUs including 52-toneRUs and 26-tone RUs and some (i.e., MRU2, MRU3, MRU6, and MRU7) of themulti-RUs including 106-tone RUs and 26-tone RUs may not be used in thebandwidth equal to or greater than 80 MHz.

FIGS. 21A and 21B show small-size multi-RUs allocable to a STA in anOFDMA 160 MHz EHT PPDU according to an embodiment. Specifically, thetables of FIGS. 21A and 21B show indexes and combinations of thesmall-size multi-RUs allocable in a bandwidth of 160 MHz. In someembodiments, as described later with reference to FIGS. 29A and 29B,values of RU allocation subfields may increase in the order of theindexes shown in FIGS. 21A and 21B.

Referring to FIG. 21A, the multi-RUs including 52-tone RUs and 26-toneRUs may have 24 different combinations, and may be indexed as first to24th multi-RUs MRU1 to MRU24. Referring to FIG. 21B, the multi-RUincluding a 106-tone RU and a 25-tone RU may have 16 differentcombinations, and may be indexed as the first to sixteenth multi-RUsMRU1 to MRU16.

FIGS. 22A, 22B, and 22C show small-size multi-RUs allocable to a STA inan OFDMA 320 MHz EHT PPDU according to an embodiment. Specifically, thetables of FIGS. 22A, 22B, and 22C show indexes and combinations ofsmall-size multi-RUs allocable in a bandwidth of 320 MHz. In someembodiments, as described later with reference to FIGS. 29A and 29B,values of RU allocation subfields may increase in the order of theindexes illustrated in FIGS. 22A, 22B, and 22C.

Referring to FIGS. 22A and 22B, the multi-RU including a 52-tone RU anda 26-tone RU may have 48 different combinations, and may be indexed asfirst to 48th multi-RUs MRU1 to MRU48. Referring to FIG. 22C, themulti-RU including a 106-tone RU and a 25-tone RU may have 32 differentcombinations, and may be indexed as the first to 32nd multi-RUs MRU1 toMRU32.

FIG. 23 shows large-size multi-RUs allocable to a STA in an OFDMA 80 MHzEHT PPDU according to an embodiment. Specifically, the table of FIG. 23shows indexes and combinations of the large-size multi-RUs allocable ina bandwidth of 80 MHz. In some embodiments, as described later withreference to FIGS. 29A and 29B, values of RU allocation subfields mayincrease in the order of the indexes shown in FIG. 23 .

Referring to FIG. 23 , the multi-RUs including 484-tone RUs and 242-toneRUs may have four different combinations, and may be indexed as thefirst to fourth multi-RUs MRU1 to MRU4.

FIG. 24 shows large-size multi-RUs allocable to a STA in an OFDMA 160MHz EHT PPDU according to an embodiment. Specifically, the table of FIG.24 shows indexes and combinations of large-size multi-RUs allocable in abandwidth of 160 MHz. In some embodiments, as described later withreference to FIGS. 29A and 29B, values of RU allocation subfields mayincrease in the order of the indexes illustrated in FIG. 24 .

Referring to FIG. 24 ,

-   -   the multi-RU including 484-tone RUs and 242-tone RUs may have        eight different combinations and may be indexed as the first to        eighth multi-RUs MRU1 to MRU8. In a bandwidth of 160 MHz, four        484-tone RUs may be sequentially arranged, and eight 242-tone        RUs may be sequentially arranged. As shown in FIG. 24 , the        first to eighth multi-RUs may respectively correspond to        combinations of sequentially unallocated eight 242-tone RUs.

The multi-RUs including 996-tone RUs and 484-tone RUs may have fourdifferent combinations, and may be indexed as the first to fourthmulti-RUs MRU1 to MRU4. In a bandwidth of 160 MHz, two 996-tone RUs maybe sequentially arranged, and four 484-tone RUs may be sequentiallyarranged. As shown in FIG. 24 , the first to fourth multi-RUs MRU1 toMRU4 may respectively correspond to combinations of sequentiallyunallocated four 484-tone RUs.

The multi-RUs including 996-tone RUs, 484-tone RUs, and 242-tone RUs mayhave 8 different combinations, and may be indexed as the first to eighthmulti-RUs MRU1 to MRU8. In a bandwidth of 160 MHz, two 996-tone RUs maybe sequentially arranged, four 484-tone RUs may be sequentiallyarranged, and eight 242-tone RUs may be sequentially arranged. As shownin FIG. 24 , the first to eighth multi-RUs MRU1 to MRU8 may respectivelycorrespond to combinations of sequentially unallocated eight 242-toneRUs.

FIGS. 25A, 25B, and 25C show large-size multi-RUs allocable to a STA inan OFDMA 320 MHz EHT PPDU according to an embodiment. Specifically,FIGS. 25A, 25B, and 25C show separate tables for illustration purposes,and the tables of FIGS. 25A, 25B and show indexes and combinations ofthe large-size multi-RUs allocable in a bandwidth of 320 MHz. In someembodiments, as described later with reference to FIGS. 29A and 29B,values of RU allocation subfields may increase in the order of theindexes shown in FIGS. 25B, and 25C.

Referring to FIG. 25A, multi-RUs including 484-tone RUs and 242-tone RUsmay have 16 different combinations, and may be indexed as the first tosixteenth multi-RUs MRU1 to MRU16. In a bandwidth of 320 MHz, eight484-tone RUs may be sequentially arranged, and sixteen 242-tone RUs maybe sequentially arranged. As shown in FIG. 25A, the first to sixteenthmulti-RUs may respectively correspond to combinations of sequentiallyunallocated sixteen 242-tone RUs.

The multi-RUs including 996-tone RUs and 484-tone RUs may have eightdifferent combinations, and may be indexed as the first to eighthmulti-RUs MRU1 to MRU8. In a bandwidth of 320 MHz, four 996-tone RUs maybe sequentially arranged, and eight 484-tone RUs may be sequentiallyarranged. As shown in FIG. 25A, the first to eighth multi-RUs MRU1 toMRU8 may respectively correspond to combinations of sequentiallyunallocated eight 484-tone RUs.

Referring to FIG. 25B, multi-RUs including 996-tone RUs, 484-tone RUs,and 242-tone RUs may have 16 different combinations, and be indexed asthe first to sixteenth multi-RUs MRU1 to MRU16. In a bandwidth of 320MHz, four 996-tone RUs may be sequentially arranged, eight 484-tone RUsmay be sequentially arranged, and sixteen 242-tone RUs may besequentially arranged. As shown in FIG. 25B, the first to sixteenthmulti-RUs MRU1 to MRU16 may respectively correspond to combinations ofsequentially unallocated sixteen 242-tone RUs.

A multi-RU including two 996-tone RUs and 484-tone RUs may have 12different combinations, and may be indexed as the first to twelfthmulti-RUs MRU1 to MRU12. In a bandwidth of 320 MHz, the first to fourth996-tone RUs may be sequentially arranged and the first to eighth484-tone RUs may be sequentially arranged. As shown in FIG. 25B, thefirst to fifth multi-RUs MRU1 to MRU6 may respectively correspond tocombinations of the sequentially unallocated first to sixth 484-tone RUswhile the fourth 996-tone RU is not allocated. In addition, the seventhto twelfth multi-RUs MRU7 to MRU12 may respectively correspond tocombinations of the sequentially unallocated third to eighth 484-toneRUs while the first 996-tone RU is not allocated.

Referring to FIG. 25C, a multi-RU including three 996-tone RUs may havefour different combinations, and may be indexed as the first to fourthmulti-RUs MRU1 to MRU4. In a 320 MHz bandwidth, four 996-tone RUs may besequentially arranged, and as shown in FIG. 25C, the first to fourthmulti-RUs MRU1 to MRU4 may respectively correspond to combinations ofsequentially unallocated four 996-tone RUs.

A multi-RU including three 996-tone RUs and a 484-tone RU may have 8different combinations, and may be indexed as the first to eighthmulti-RUs MRU1 to MRU8. In a 320 MHz bandwidth, four 996-tone RUs may besequentially arranged and eight 484-tone RUs may be sequentiallyarranged. As shown in FIG. 25C, the first to eighth multi-RUs MRU1 toMRU8 may respectively correspond to combinations of sequentiallyunallocated eight 484-tone RUs.

In EHT, a user information field may define not only single RUs of HEbut also the multi-RUs described above with reference to FIGS. 18 to25C. Hereinafter, examples of the user information field defining singleRUs and multi-RUs in an extended bandwidth of EHT will be described.

FIG. 26 is a flowchart illustrating a method of communication based onan extended bandwidth and multi-RUs according to an embodiment.Specifically, FIG. 26 shows an example of operation S30 of FIG. 17 . Asdescribed above with reference to FIG. 17 , the AP may generate at leastone subfield in operation S30′ of FIG. 26 . Nine bits or more includedin a user information field may be used to define at least one RUallocated in EHT. As described above with reference to FIG. 16A, an RUallocation subfield may have a length of 9 bits, and the 9 bits mayinclude a first group of 7 bits and a second group of 2 bits to bedescribed later. In other examples, as described above with reference toFIG. 16B, the RU allocation subfield may have a length of 8 bits, andthe 8 bits may include at least 7 bits to be described later. The groupof at least 2 bits to be described later may include one bit of the RUallocation subfield and one bit of a PS160 subfield. As shown in FIG. 26, operation S30′ may include a plurality of operations S31 to S37, whichwill be described with reference to FIG. 17 .

Referring to FIG. 26 , in operation S31, the AP 10 may set “K” bits,where the K is at least 7 and the K bits are associated with at leastone RU. For example, the AP 10 may set K bits of the RU allocationsubfield in association with the at least one RU allocated to the STA inoperation S20 of FIG. 17 . The at least one RU may be defined in asubband with only the K bits, or may be defined based on at least onebit of the M bits (where M is at least two) described later, as well asthe K bits. The M bits of the user information field may be set inoperations (i.e., S32 to S37) following operation S31.

In operation S32, the AP 10 may determine whether the bandwidthcorresponds to two subbands. Herein, a subband may refer to a minimumfrequency band including the at least one RU allocated to the STA 20,that is, a frequency band including a channel, and may have a width ofe.g., 80 MHz, 160 MHz, or 320 MHz. Herein, the subband may be simplyreferred to in terms of its width. Accordingly, the cases where thebandwidth corresponds to two subbands in EHT may include a case wherethe subband is 80 MHz in a bandwidth of 160 MHz and the case where thesubband is 160 MHz in a bandwidth of 320 MHz. When the bandwidthincludes a plurality of subbands, the plurality of subbands may includea primary subband and at least one secondary subband. Management andcontrol information may be transmitted in a primary subband but may notbe transmitted in a secondary subband.

When the bandwidth corresponds to two subbands, in operation S33, the AP10 may set one bit as a value defining a subband including at least oneRU, and in operation S34, the AP 10 may set another bit associated withthe at least one RU. That is, one of the M=2 bits of the userinformation field may represent one of the two subbands, and the otherof the M=2 bits may define the at least one RU along with the K bits.(Since the K bits and the M bits collectively define the at least oneRU, each of the K bits and the M bits are associated with the at leastone RU.)

When the bandwidth does not correspond to two subbands, in operationS35, the AP may determine whether the bandwidth corresponds to four ormore subbands. For example, cases where the bandwidth corresponds tofour subbands in EHT may include a case where the subband is 80 MHz in abandwidth of 320 MHz.

When the bandwidth includes four or more subbands, in operation S36, theAP 10 may set the M bits as a value defining a subband including atleast one RU. For example, the value may be a decimal value defined bythe binary sequence of the M bits. Accordingly, the M bits of the userinformation field may define one of four or more subbands including atleast one RU defined in part by the K bits set in operation S31.

When the bandwidth does not include four or more subbands, e.g., whenthe bandwidth includes a single subband, in operation S37, the AP 10 mayset the M bits associated with the at least one RU. For example, thecases where the bandwidth includes the single subband in EHT includesthe case where the bandwidth is 20 MHz, 40 MHz, or 80 MHz, the casewhere the subband is 160 MHz in the bandwidth of 160 MHz, and the casewhere the subband is 320 MHz in the bandwidth of 320 MHz.

FIG. 27 is a flowchart illustrating a method of communication based onan extended bandwidth and multi-RUs according to an embodiment.Specifically, FIG. 27 shows an example of operation S80 of FIG. 17 . Asdescribed above with reference to FIG. 17 , in operation S80′ of FIG. 27, the STA 20 may identify at least one RU allocated to the STA 20. Insome embodiments, as described above with reference to FIG. 16A, an RUallocation subfield may have a length of 9 bits, and 9 bits may includeat least 7 bits and at least 2 bits described below. In addition, insome embodiments, as described above with reference to FIG. 16B, the RUallocation subfield may have a length of 8 bits, and the 8 bits mayinclude at least 7 bits to be described later. The at least 2 bits to bedescribed later may include one bit of the RU allocation subfield andone bit of the PS160 subfield. As shown in FIG. 27 , operation S80′ mayinclude a plurality of operations S81 to S87. Hereinafter, a descriptionof FIG. 27 that is redundant with the description of FIG. 26 will beomitted, and FIG. 26 will be described with reference to FIG. 17 .

Referring to FIG. 27 , in operation S81, the STA 20 may identify atleast one RU based on K (at least 7) bits. The STA 20 may identify atleast one RU defined in a subband with only the K bits, and may identifyat least one RU based on at least one bit of the M (at least 2) bits tobe described later as well as the K bits. The K bits of the userinformation field may be analyzed in operations (i.e., S82 to S87)following operation S81.

In operation S82, the STA 20 may determine whether a bandwidthcorresponds to two subbands. When the bandwidth corresponds to the twosubbands, in operation S83, the STA may identify the subband includingthe at least one RU based on one bit of M bits, and in operation S84 theSTA 20 may identify the at least one RU based on the other bit(s) of theM bits. Hereafter, examples are described in which M equals two.

When the bandwidth does not correspond to the two subbands, in operationS85, the STA 20 may determine whether the bandwidth corresponds to fouror more sub-bands. When the bandwidth includes four or more subbands, inoperation S86, the STA 20 may identify a subband including the at leastone RU based on the M bits. When the bandwidth does not include four ormore subbands, the STA 20 may identify the at least one RU based on theM bits in operation S87.

FIGS. 28A and 28B are diagrams illustrating examples of a userinformation field according to example embodiments. Specifically, FIG.28A illustrates an example of an RU allocation subfield included in auser information field, and FIG. 28B illustrates an example of a userinformation field including the RU allocation subfield and a PS160subfield.

Referring to FIG. 28A, the RU allocation subfield may include 9 bits,that is, first to ninth bits X0 to X8. The third to ninth bits X2 to X8may correspond to at least 7 bits in FIGS. 26 and 27 , and the first andsecond bits X0 and X1 may correspond to at least 2 bits in FIGS. 26 and27 . In some embodiments, the at least 2 bits of FIGS. 26 and 27 mayinclude a least significant bit (LSB) of the RU allocation subfield asshown in FIG. 28A, and may include a most significant bit (MSB) or boththe LSB and the MSB differently from that shown in FIG. 28A.

Referring to FIG. 28A, as described above with reference to FIGS. 26 and27 , when a bandwidth includes a plurality of subbands, the first bit X0and/or the second bit X1 may define one of the plurality of subbands. Asshown in a first table T1 of FIG. 28A, when the subband is 80 MHz in abandwidth of 160 MHz, the second bit X1 may define a lower 80 MHz or anupper 80 MHz, and when the subband is 80 MHz in a bandwidth of 320 MHz,the first and second bits X0 and X1 may define one of lower 80 MHz andupper 80 MHz in the lower 160 MHz, and lower 80 MHz and upper 80 MHz inthe upper 160 MHz. Accordingly, the second bit X1 of the RU allocationsubfield defining at least one RU allocated to a primary 80 MHz in abandwidth of 160 MHz may correspond to ‘0’, and the second bit X1 of theRU allocation subfield defining at least one RU allocated to a secondary80 MHz may correspond to ‘1’.

A second table T2 of FIG. 28A represents values of the first and secondbits X0 and X1 for indicating at least one RU allocated to each 80 MHzaccording to a position of the primary 160 MHz and/or the primary 80 MHzin the bandwidth of 320 MHz. In the bandwidth of 160 MHz, the first bitX0 may be zero, and a third table T3 of FIG. 28A represents a value ofthe second bit X1 for indicating the at least one RU allocated to each80 MHz according to the position of the primary 80 MHz in the bandwidthof 160 MHz. In a bandwidth of 80 MHz or less, the first bit X0 and thesecond bit X1 may be zero.

Referring to FIG. 28B, in some embodiments, the user information fieldmay include an RU allocation subfield of 8 bits and a PS160 subfield of1 bit. As shown in FIG. 28B, the RU allocation subfield may includefirst to eighth bits B0 to B7, and the PS160 subfield may include bitsBx. In some embodiments, the second to eighth bits B1 to B7 of the RUallocation subfield may correspond to at least 7 bits of FIGS. 26 and 27, and the first bit B0 of the RU allocation subfield and the bit Bx ofthe PS160 subfield may correspond to at least 2 bits of FIGS. 26 and 27. In some embodiments, the first bit B0 of the RU allocation subfieldmay be an LSB of the RU allocation subfield as shown in FIG. 28B, or maybe an MSB different from that shown in FIG. 28B.

Referring to FIG. 28B, as described above with reference to FIGS. 26 and27 , when a bandwidth includes a plurality of subbands, the first bit B0of the RU allocation subfield and the bit Bx of the PS160 subfield maydefine one subband among a plurality of subbands. In some embodiments,the first bit B0 of the RU allocation subfield may indicate a primary 80MHz or a secondary 80 MHz for a single RU and/or multi-RUs of 80 MHz orless in the primary 160 MHz. In addition, the first bit B0 of the RUallocation subfield may be used to index multi-RUs with respect to asingle RU and/or multi-RUs greater than 80 MHz. The bit Bx of the PS160subfield may indicate a primary 160 MHz or a secondary 160 MHz withrespect to a single RU and/or multi-RUs of 160 MHz or less. In addition,the bit Bx of the PS160 subfield may be used to index multi-RUs withrespect to a single RU and/or multi-RUs greater than 160 MHz.Accordingly, the first bit X0 and the second bit X1 of FIG. 28A may bederived from the first bit B0 of the RU allocation subfield and the bitBx of the PS160 subfield according to conditions defined by a pseudocode (CD) of FIG. 28B.

A fourth table T4 of FIG. 28B represents values of the first bit X0 andthe second bit X1 of FIG. 28A respectively calculated from the first bitB0 of the RU allocation subfield and the bit Bx of the PS160 subfieldaccording to the position of the primary 160 MHz and/or the primary 80MHz in the bandwidth of 320 MHz. For example, as shown in FIG. 28B, whenthe secondary 80 MHz, the primary 80 MHz, and the secondary 160 MHz aresequentially arranged ([S80 P80 S160]), the first bit X0 of FIG. 28A maybe same with the bit Bx of the PS160 subfield, and the second bit X1 ofFIG. 28A may correspond to a negation (or a logical complement) of alogical sum (or an XOR operation result) of the first bit B0 of the RUallocation subfield and the bit Bx of the PS160 subfield. In addition, afifth table T5 of FIG. 28B represents values of the first bit X0 and thesecond bit X1 of FIG. 28A calculated from the first bit B0 of the RUallocation subfield and the bit Bx of the PS160 subfield according tothe position of the primary 80 Mhz in the bandwidth of 160 MHz. The bitBx of the PS160 subfield may be zero in the bandwidth of 160 MHz. Inaddition, the bit Bx of the PS160 subfield and the first bit B0 of theRU allocation subfield may be zero in a bandwidth of 80 MHz or less.Hereinafter, the example of FIG. 28A will be mainly described, but it isnoted that embodiments may also be applied to the example of FIG. 28B.

FIGS. 29A and 29B are diagrams illustrating an RU allocation subfieldaccording to an embodiment. Specifically, FIGS. 29A and 29B representseparate tables for illustration purposes, and the tables of FIGS. 29Aand 29B represent values of the RU allocation subfield and single RUs ormulti-RUs corresponding to the values.

Referring to FIG. 29A, a small-size single RU, a small-size multi-RU,and multi-RUs including a 484-tone RU and a 242-tone RU may be includedin subband of 80 MHz or less. Accordingly, as illustrated in FIG. 29A,the first and second bits X0 and X1 of the RU allocation subband maydefine a channel position, that is, a subband to which at least one RUis allocated. To define the small-size single RU, a small-size multi-RUdescribed above with reference to FIGS. 18 to 25C, and multi-RUsincluding 484-tone RUs and 242-tone RUs, 7 bits of the RU allocationsubband, that is, the third to ninth bits X2 to X8, may have values asshown in FIG. 29A.

An index of an RU may be calculated from the first and second bits X0and X1. In some embodiments, as shown in FIG. 29A, a variable N may becalculated as “2*X0+X1”, and the RU index may be calculated from thevariable N. For example, an index of a 26-tone RU may correspond to asum of “37*N” and an RU index of EHT, an index of a 52-tone RU maycorrespond to a sum of “16*N” and the RU index of EHT, an index of a106-tone RU may correspond to a sum of “8*N” and the RU index of EHT, anindex of a 242-tone RU may correspond to a sum of “4*N” and the RU indexof EHT, an index of a 484-tone RU may correspond to a sum of “2*N” andthe RU index of EHT, and an index of a 996-tone RU may correspond to asum of N and the RU index of EHT. An index of a multi-RU including two996-tone RUs may correspond to a sum of the first bit X0 and the RUindex of EHT, an index of a multi-RU including four 996-tone RUs may be1, an index of a multi-RU including a 52-tone RU and a 26-tone RU maycorrespond to a sum of “12*N” and the RU index of EHT, an index of amulti-RU including a 106-tone RU and a 26-tone RU may correspond to asum of “8*N” and the RU index of EHT, and an index of a multi-RUincluding a 484-tone RU and a 242-tone RU may correspond to a sum of“4*N” and the RU index of EHT. Referring to FIG. 29B, to define alarge-size multi-RU, except for the multi-RU including the 484-tone RUand the 242-tone RU, the first to ninth bits X0 to X8 of the RUallocation subband may have a value as shown in FIG. 29B. The index ofthe multi-RU of FIG. 29B may be calculated from the first bit X0. Forexample, an index of a multi-RU including the 996-tone RU and the484-tone RU may correspond to a sum of “4*X0” and the RU index of EHT,and an index of a multi-RU including the 996-tone RU, the 484-tone RUand the 242-tone RU may correspond to a sum of “8*X0” and the RU indexof EHT. Indexes of the remaining multi-RUs may be same with the RUindexes of EHT.

Values of RU allocation subbands defining large-size multi-RUs, exceptfor the multi-RUs including the 484-tone RU and the 242-tone RU, will bedescribed later with reference to FIGS. 30 to 34 .

In some embodiments, only some of the single RU and/or the multi-RUshown in FIGS. 29A and 29B may be used for multi-user (MU) transmission.For example, MU-MIMO of EHT may be possible in a single RU and/or amulti-RU corresponding to 242 or more subcarriers. Accordingly, the APmay allocate at least one RU to a plurality of multiplexed STAs, and maygenerate the RU allocation subfield for MU transmission.

In some embodiments, the RU allocation subfield for MU transmission mayhave a structure similar to the RU allocation subfield for single user(SU) transmission. For example, the RU allocation subfield for MUtransmission may include at least 6 bits representing a decimal valuethat sequentially increases according to values of the third to ninthbits X2 to X8 in cells hatched/shaded in FIG. 29A and cells shown inFIG. 29B. Accordingly, the AP may set the at least 6 bits of the RUallocation subfield based on the at least one RU for MU transmission,may set one bit of at least 2 bits to define one of the two subbandsincluded in the bandwidth, and may set two bits of at least 2 bits todefine one of four subbands included in the bandwidth. Accordingly, theRU allocation subfield for MU transmission may have a length of at least8 bits.

The RU allocation subfield for MU transmission may be set independentlyfrom the RU allocation subfield for SU transmission. For example, the RUallocation subfield may have one of values for representing 28 singleRUs, that is, sixteen 242-tone RUs, eight 484-tone RUs, and four996-tone RUs. In addition, the RU allocation subfield may have one ofvalues for representing 67 multi-RUs, that is, two multi-RUs eachincluding two 996-tone RUs, a multi-RU including four 996-tone RUs, 16multi-RUs each including a 484-tone RU and a 242-tone RU, 8 multi-RUseach including a 996-tone RU and a 484-tone RU, 6 multi-RUs eachincluding a 996-tone RU, a 484-tone RU and a 242-tone RU, 12 multi-RUseach including two 996-tone RUs and a 484-tone RU, 4 multi-RUs eachincluding three 996-tone RUs, and 8 multi-RUs each including three996-tone RUs and a 484-tone RU. Accordingly, the RU allocation subfieldfor MU transmission may have one of a total of 95 values, and to thisend, may have a length of at least 7 bits.

FIG. 30 shows values of multi-RUs including a 996-tone RU and a 484-toneRU and an RU allocation subfield according to an embodiment. In thiscase, the multi-RUs including the 996-tone RU and the 484-tone RU mayhave four different combinations within a subband, e.g., 160 MHz, asdescribed above with reference to FIG. 24 . Accordingly, the first bitX0 among the first and second bits X0 and X1 of the RU allocationsubfield may define a subband (e.g., 160 MHz) including multi-RUs in abandwidth of 320 MHz, whereas the second bit X1 may define multi-RUstogether with the third to ninth bits X2 to X8. In particular, as shownin FIG. 30 , the second and third bits X1 and X2 may represent locationsof unallocated 484-tone RUs in the subband (e.g., 160 MHz). Accordingly,as described above with reference to FIGS. 24 and 25A, to definemulti-RUs indexed based on the location of the unallocated 484-tone RU,the RU allocation subfield may have values shown in FIGS. 29B and 30 .It is noted that herein, “unallocated” RUs may be “punctured” RUs, inwhich puncture frequencies of the RU are frequencies that are not used.Such puncturing of frequencies may be implemented to avoid interferencewith another AP that is using those frequencies in a communication withanother STA.

FIG. 31 shows values of multi-RUs including a 996-tone RU, a 484-toneRU, and a 242-tone RU and an RU allocation subfield according to anembodiment. Here, the multi-RUs including the 996-tone RU, the 484-toneRU, and the 242-tone RU, as described above with reference to FIG. 24 ,may have eight different combinations within a subband, e.g., 160 MHz.Accordingly, the first bit X0 among the first and second bits X0 and X1of the RU allocation subfield may define the subband (e.g., 160 MHz)including multi-RUs in a bandwidth of 320 MHz, and the second bit X1 maydefine multi-RUs together with the third to ninth bits X2 to X8. Inparticular, as shown in FIG. 31 , the second to fourth bits X1 to X3 mayindicate a location of the unallocated 242-tone RU in the subband (e.g.,160 MHz). Accordingly, as described above with reference to FIGS. 24 and25B, to define multi-RUs indexed based on the location of theunallocated 242-tone RU, the RU allocation subfield may have valuesshown in FIGS. 29B and 31 . (As noted earlier, a punctured RU is anexample of an unallocated RU.)

FIG. 32 shows values of multi-RUs including two 996-tone RUs and484-tone RUs and an RU allocation subfield according to an embodiment.In FIG. 32 , the multi-RU including the two 996-tone RUs and the484-tone RU may have 12 different combinations within a subband, e.g.,320 MHz, as described above with reference to FIG. 25B. Accordingly, thefirst and second bits X0 and X1 of the RU allocation subfield may definemulti-RUs together with the third to ninth bits X2 to X8. As shown inFIG. 32 , the first bit X0 may represent a location of an unallocated996-tone RU in the subband (e.g., 320 MHz), and the second to fourthbits X1 to X3 may represent a location of an unallocated 484-tone RU.Accordingly, as described above with reference to FIG. 25B, to definemulti-RUs indexed based on the locations of the unallocated 996-tone RUand 484-tone RU, the RU allocation subfield may have values shown inFIGS. 29B and 32 .

FIG. 33 shows values of multi-RUs including three 996-tone RUs and an RUallocation subfield according to an embodiment. Referring to FIG. 33 ,the multi-RU including the three 996-tone RUs may have four differentcombinations within a subband, that is, 320 MHz, as described above withreference to FIG. 25C. Accordingly, the first and second bits X0 and X1of the RU allocation subfield may define multi-RUs together with thethird to ninth bits X2 to X8. In particular, as shown in FIG. 33 , thefirst and second bits X0 and X1 may represent locations of unallocated996-tone RUs in the subband (e.g., 320 MHz). Accordingly, as describedabove with reference to FIG. 25C, to define the multi-RU indexed basedon the locations of the unallocated 996-tone RU, the RU allocationsubfield may have values shown in FIGS. 29B and 33 .

FIG. 34 shows values of multi-RUs including three 996-tone RUs and484-tone RUs and an RU allocation subfield according to an embodiment.In this case, the multi-RU including the three 996-tone RUs and the484-tone RUs may have eight different combinations within a subband,that is, 320 MHz, as described above with reference to FIG. Accordingly,the first and second bits X0 and X1 of the RU allocation subfield maydefine multi-RUs together with the third to ninth bits X2 to X8. Asshown in FIG. 34 , the first to third bits X0 to X2 may representlocations of unallocated 484-tone RUs in the subband (e.g., 320 MHz).Accordingly, as described above with reference to FIG. 25C, to definethe multi-RU indexed based on the locations of the unallocated 484-toneRU, the RU allocation subfield may have values shown in FIGS. 29B and 34.

FIG. 35 is a diagram illustrating an RU allocation subfield according toan embodiment. In some embodiments, as shown in FIG. 35 , the RUallocation subfield may include 9 bits, e.g., the first to ninth bits X0to X8. Compared with the example of FIG. 28 , the RU allocation subfieldof FIG. 35 may include the first bit X0 for defining one of twosubbands, that is, a lower 160 MHz and an upper 160 MHz, in a bandwidthof 320 MHz, and may include the second to ninth bits X1 to X8 fordefining at least one RU. Accordingly, based on at least one RUallocated to a STA, that is, a single RU or the multi-RUs describedabove with reference to FIGS. 18 to 25C, an AP may set at least 8 bits,e.g., the second to ninth bits X1 to X8. In addition, the AP may set thefirst bit X0 to a value representing one of a lower 160 MHz and an upper160 MHz when the subband is 160 MHz in a bandwidth of 320 MHz.

While aspects of the inventive concept have been particularly shown anddescribed with reference to embodiments thereof, it will be understoodthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the inventive concept as definedby the following claims and their equivalents.

1. A method of communicating, by a first device, with at least onesecond device in a wireless local area network (WLAN) system, the methodcomprising: allocating a multi-resource unit (RU) within a bandwidth tothe at least one second device, the multi-RU including at least twosingle RUs; generating at least one subfield defining the multi-RU; andtransmitting a physical protocol layer data unit (PPDU) including the atleast one subfield to the at least one second device, wherein thegenerating the at least one subfield comprises generating at least sevenbits based on a size of the multi-RU.
 2. The method of claim 1, whereinthe generating of the at least one subfield further comprises generatingat least one bit indicating a subband where the multi-RU is locatedwithin the bandwidth when the size of the multi-RU is smaller than thesubband.
 3. The method of claim 2, wherein the generating of at leastone bit comprises generating a first bit and a second bit indicating thesubband among four subbands within the bandwidth.
 4. The method of claim3, wherein the generating at least one subfield comprises: generating afirst subfield including the first bit; and generating a second subfieldincluding the second bit and the at least seven bits.
 5. The method ofclaim 2, wherein the generating at least one bit comprises: generating afirst bit indicating the subband among two subbands within thebandwidth; and generating a second bit indicating the at least twosingle RUs in combination with the at least seven bits.
 6. The method ofclaim 5, wherein the generating at least one subfield comprises:generating a first subfield including the first bit; and generating asecond subfield including the second bit and the at least seven bits. 7.The method of claim 1, wherein the generating the at least one subfieldcomprises generating a first bit and a second bit indicating the atleast two single RUs in combination with the at least seven bits whenthe size of the multi-RU is greater than a subband.
 8. The method ofclaim 7, wherein the first bit and the second bit indicate a subbandincluding at least one single RU that is unallocated to the at least onesecond device, when the size of the multi-RU is equal to or greater thanthree subbands among four subbands within the bandwidth.
 9. The methodof claim 8, wherein the generating the at least seven bits comprisessetting the at least seven bits to a first value when the size of themulti-RU corresponds to the three subbands.
 10. The method of claim 8,wherein the at least seven bits indicate the at least one single RU whenthe size of the multi-RU is less than the three subbands.
 11. The methodof claim 7, wherein the generating at least one sub-field comprises:generating a first subfield including the first bit; and generating asecond subfield including the second bit and the at least seven bits.12. A method of communicating, by a second device, with a first devicein a wireless local area network (WLAN) system, the method comprising:receiving a physical protocol layer data unit (PPDU) from the firstdevice; extracting at least one subfield defining a multi-resource unit(RU) allocated to the second device within a bandwidth, the multi-RUincluding at least two single RUs; and identifying the multi-RU based onthe at least one subfield, wherein the identifying the multi-RUcomprises identifying a size of the multi-RU based on at least sevenbits included in the at least one subfield.
 13. The method of claim 12,wherein the identifying the multi-RU comprises identifying a subbandwhere the multi-RU is located within the bandwidth based on at least onebit included in the at least one subfield when the size of the multi-RUis smaller than the subband.
 14. The method of claim 13, wherein theidentifying of the subband comprises identifying the subband among foursubbands within the bandwidth based on a first bit and a second bitincluded in the at least one subfield.
 15. The method of claim 14,wherein the extracting the at least one subfield comprises: extracting afirst subfield including the first bit; and extracting a second subfieldincluding the second bit and the at least seven bits.
 16. The method ofclaim 13, wherein the identifying the multi-RU comprises: identifyingthe subband among two subbands within the bandwidth based on a first bitincluded in the at least one subfield; and identifying the at least oneRU based on a combination of a second bit and the at least seven bits,the second bit being included in the at least one subfield.
 17. Themethod of claim 16, wherein the extracting the at least one subfieldcomprises: extracting a first subfield including the first bit; andextracting a second subfield including the second bit and the at leastseven bits.
 18. The method of claim 12, wherein the identifying themulti-RU comprises: identifying the at least two single RUs based on afirst bit, a second bit and the at least seven bits when the size of themulti-RU is greater than a subband, the first bit and the second bitbeing included in the at least one subfield.
 19. The method of claim 18,wherein the first bit and the second bit indicate a subband including atleast one single RU that is unallocated to the at least one seconddevice, when the size of the multi-RU is equal to or greater than threesubbands among four subbands within the bandwidth.
 20. The method ofclaim 19, wherein the at least seven bits indicate the at least onesingle RU when the size of the multi-RU is greater than the threesubbands.